The home energy storage market is shifting toward all-in-one solutions and higher charging capacities to meet rising energy demands. These systems actively support both new installations (incremental) and existing (stock) residential photovoltaic (PV) markets.

Home energy storage systems (HESS) often integrate with residential photovoltaic setups, rapidly increasing installed capacity. The core of HESS, known as Battery Energy Storage Systems (BESS), includes a rechargeable battery—typically lithium-ion or lead-acid—managed by intelligent software and hardware to efficiently control charge and discharge cycles. Coupling HESS with distributed PV generation completes a home PV storage system, reducing energy costs for users while mitigating power outages. For the grid, energy storage systems provide stability during peak demand and offer frequency regulation.

Two main coupling types define home energy storage systems: DC coupling and AC coupling, which address the incremental and stock PV markets, respectively. The incremental market, focused on new installations, drives the industry’s primary growth.

1. Incremental Market (Newly Installed PV + Energy Storage Systems):
   New installations typically favor DC coupling products. A DC-coupled system combines a battery and a hybrid inverter, allowing it to function as both a PV grid inverter and an energy storage inverter. DC coupling enables both PV and storage batteries to convert energy through one hybrid inverter, removing the need for a separate PV inverter. This setup increases system integration, simplifies installation and after-sales service, and allows for intelligent monitoring and control. Many households with pre-existing PV installations find that upgrading to a hybrid inverter enables unified energy management.
2. Stock Market (Existing PV Installations Adding Energy Storage Systems):
   AC coupling products best suit households with existing PV systems, as they require only additional batteries and an energy storage inverter, leaving the original PV setup unaffected. AC coupling offers a safety advantage by aggregating energy on the AC side, allowing direct use by the load, grid supply, or storage in the battery via a bidirectional inverter. This approach supports low-voltage PV and batteries, reducing DC high-voltage risks and boosting overall system safety.